Teenager Mariah Mundi (Aneurin Barnard) finds himself completely mystified by the disappearance of his parents (Ioan Guffudd and Keeley Hawes) in 1885 London, and is further confounded by the kidnapping of his younger brother Felix (Xavier Atkins). He soon discovers that the reasons for these occurrences have to do with the magical Midas Box that has the power to transform things into gold, and his parents' involvement as secret agents with the mysterious Bureau of Antiquities.

With the aid of another super-skilled and very dashing agent, Will Charity (Michael Sheen), Mariah tries to track down his relatives and winds up at a vast hotel where he encounters Otto Luger (Sam Neill), its malevolent owner, and his henchwoman Monica (Lena Headey), who are both obviously involved in the heinousness and want that box at any cost.

Everyone involved in The Adventurer: the Curse of the Midas Box works mightily to put this over—a new but old-fashioned, sturdy adventure epic meant to appeal to the entire family. It's been given a handsome Victorian production with all manner of visual niceties, some Dickensian flavor and a strong cast, and yet stubbornly remains a quite flat, strangely impersonal and unaffecting affair. Jonathan Newman's direction is efficient but direly lacking in ingenuity, but the script is probably the biggest culprit here, bleakly derivative, seemingly cobbled together from remnants of Indiana Jones and Harry Potterfilms and generations of others before them. An army of imprisoned children which Mariah discovers is pretty much indicative of what I'm talking about: We see these poor ragamuffins slaving away for the villains, but they are basically just set decoration for which we feel nothing. And when we finally do get to that magical box in question, it turns out to be a sadly un-magical, anachronistically modern-looking objet, its powers nothing more than a son et lumiere amalgam of the cheesiest CGI effects. And in a corrupt nod to present-day movie tastes for violence and more violence, it's not enough that the box turns things to gold, it must also destroy people as well. Things are definitely not helped by a callously tacked-on scene that more than hints at a sequel to this would-be franchise, involving Mariah's mummified mother.

The performances do little to humanize the mechanical quality of the script. Barnard and Atkins are rather pretty, and that's about it; since they’re not truly engaging, you never quake for their variously imperiled states. The talented Headey is wasted in a sketchily devised villainess role. Neill seems to revel in being a bespoke form of evil incarnate, while seriously channeling James Mason. Sheen, an improbable choice as action hero, substitutes an indefatigable and eventually monotonous puckishness for the authentically stirring heroic dash Errol Flynn supplied so easily, along with the charismatic bemusement which made you believe and happily go along for the sweeping ride.